Nonlinear viscoelastic behavior of rubber in shear

The behavior in creep under constant load and recovery following removal of load is considered for certain nonlinear mechanical models. These models consist of a linear dashpot in parallel with a non‐Hookean spring for which the ratio deformation/stress increases with stress. Some data are presented on the nonlinear creep and recovery behavior in shear of raw and vulcanized rubbers. One of the models represents to a first approximation the deviations from linear viscoelastic behavior manifested by the rubber tested.